Muffler with variable damping characteristics

Abstract

A muffler and an actuating cell provided so that the acoustic properties of the muffler can be changed. The pressure drop in the muffler is fed to the actuating cell as a control pressure. The actuating cell has a plurality of chambers which are separated by diaphragms. Each diaphragm is supported by a spring and each chamber has a pressure connection. A first pressure line feeds the total gas pressure to the overpressure side of the first diaphragm. Another pressure line directs the static gas pressure to the low-pressure side of this diaphragm. Attached to the diaphragm is a piston rod which carries a valve closing element which closes or opens a gas feed pipe.

We claim: 
     
       1. A muffler with variable damping characteristics for pulsing gases, comprising: a housing; a gas feed pipe mounted to the housing; a plurality of pipes mounted in the housing so as to be in fluid communication with the gas feed pipe; and actuating means mounted to the housing and including an actuating cell having a plurality of chambers which are separated by diaphragms, a plurality of springs, one of the springs being respectively mounted at each diaphragm so as to support the respective diaphragm, each chamber being configured to have a pressure connection the actuating cell further having a piston rod, a valve disk closing element mounted to the piston rod, a first pressure line which directs total gas pressure to an overpressure side of the diaphragm and a second pressure line which directs static gas pressure to a low-pressure side of the diaphragm, the valve disk being movably arranged in one of the pipes, the actuating means being operative to move the valve disk to control gas flow in the one pipe. 
     
     
       2. A muffler according to claim 1, wherein the first and second pressure lines are formed in the piston rod, the first pressure line being arranged to open out at a head of the piston rod, the second pressure line being arranged to open out laterally in the piston rod at a distance from the head of the piston rod and at a distance from the valve disk. 
     
     
       3. A muffler according to claim 1, and further comprising a third pressure line arranged to feed a vacuum to a chamber of the plurality of chambers, the vacuum originating from the intake system of an internal combustion engine. 
     
     
       4. A muffler according to claim 1, wherein one of the chambers is configured to communicate with the atmosphere. 
     
     
       5. A muffler according to claim 1, wherein at least one of the diaphragms has one of a divergent surface and a deflecting surface. 
     
     
       6. A muffler according to claim 1, wherein the valve disk closing element includes at least one valve disk. 
     
     
       7. A muffler according to claim 6, wherein at least two valve disks are mounted to the piston rod, the valve disks having diameters that differ from one another. 
     
     
       8. A muffler according to claim 6, wherein at least two valve disks are mounted on the piston rod so as to be oriented in a mirror-inverted manner relative to one another. 
     
     
       9. A muffler according to claim 1 wherein the valve disk closing element is formed as a hollow cylinder. 
     
     
       10. A muffler according to claim 1, wherein the valve disk closing element is formed as a cylinder with a closed bottom. 
     
     
       11. A muffler according to claim 9, wherein one of the pipes in the housing is a gas feed pipe having perforations therein, the hollow cylinder being arranged in the gas feed pipe so as to be slidable over the perforations.